Turn-off dV/dt controllability in 1.2kV MOS-bipolar devices

Turn-off dV/dt controllability is an essential feature in IGBTs for flexible design in power switching applications. However, the occurrence of Dynamic Avalanche (DA) during the turn-off transients plays a key role on the turn-off power loss, dV/dt controllability and safe operating area of IGBTs. This paper aims to clarify the impact of DA on the turn-off characteristics of 1.2 kV trench IGBTs through calibrated 3-D TCAD simulations as well as experimental demonstrations. Measurement results show that DA is enhanced at high current density and high supply voltage conditions, which aggravates its influence on the dV/dt controllability as well as turn-off power loss. In order to eliminate the DA for high current density and low loss operations, a DA free design is experimentally demonstrated in the Trench Clustered IGBT (TCIGBT). Due to effective management of electric field and unique PMOS actions during turn-off, TCIGBT can retain high dV/dt controllability and low power loss at high current density operations.